Residual Stress Measurement And Research Of Nickel-based Superalloy And TiAl Alloy

Although the role of residual stresses in the material has long been concerned,but limited the testing technology and the level of awareness, there was also remained in the qualitative discussion or comparison test to study the residual stress for a long time. In recent years, the industrial sector had higher expectations for the product, the using of materials were also facing harsher conditions of service. The potential for this reason, we need to continue to develop new materials, and the need to strengthen the use of various means to give full play to the material. So the role of residual stress in the material was increasingly concerned by the industrial sector.X-ray diffraction method is currently the most mature lossless diffraction method. This method could be tested under the conditions of the residual stress without damaging the surface of the sample. Residual stress test laboratory instrument was PROTO LXRD SYSTEM. It has a high deadweight test bench, and larger test space, for larger samples may be accurately tested for residual stress.Firstly, XRD diffraction method serving larger turbine blades of different crystal faces dorsal leaf pots to do residual stress test. The experiment used Cu target to test its(420) and(331) plane, the results obtained in accordance with the diffraction peak fitting stress and stress calculation principles, the leaf basin section by tensile stress action, and the dorsal part by compressive stress action. The test results showed that different regions and grains service locations and the radius of curvature all have an impact on the residual stress.Second, chose different surface treatments polycrystalline TiAl alloy samples, test the residual stress value of each sample, use the electrolytic polishing machine for stripping layer processing for each sample. Measured results for that dued to the high-speed projectile shot peening hit the sample surface and the surface of the sample had a great plastic deformation, resulting in residual compressive stress peening large sample. And for this reason also led to stress the deepest layer of the shot peening simple,the simple of machined held the shallowest stress layer. Therefore the shot peening and blasting process might increase the depth of the material surface stress. Where in the specimen due to blasting fine particles present on the surface of which curved surface is uneven, resulting in a complete X-ray detector can not receive the information of diffraction peaks completly, so the diffraction peaks and error was terrible for blasting sample.Finally, through the fatigue text to different surface treatment processes of TiAl alloy, and text the residual stress of different point of fatigue cycle. Obtain the residual stress and the general trend did not change much. The conclusion was that bacause of the high cycle fatigue experiments, the scale fatigue of damage was so small, the role of fatigue specimens only belonged to elastic stress, the regional deformation test point did not deformed. Therefore, the residual stress values did not change the overall view. And because of the roughness specimen of surface in sandblasting sample, it had terrible deviation and test error.